Abstract-Squeezing Millimeter Waves through a Single, Nanometer-wide, Centimeter-long Slit

• Xiaoshu Chen,
• Hyeong-Ryeol Park,
• Nathan C. Lindquist,
• Jonah Shaver,
• Matthew Pelton
• & Sang-Hyun Oh

http://www.nature.com/srep/2014/141024/srep06722/full/srep06722.html

Scientific Reports

 

4,

 

Article number:

 

6722

 

doi:10.1038/srep06722

Received

 

07 August 2014 

Accepted

 

03 October 2014 

Published

 

24 October 2014

We demonstrate broadband non-resonant squeezing of terahertz (THz) waves through an isolated 2-nm-wide, 2-cm-long slit (aspect ratio of 10⁷), representing a maximum intensity enhancement factor of one million. Unlike resonant nanogap structures, a single, effectively infinitely-long slit passes incident electromagnetic waves with no cutoff, enhances the electric field within the gap with a broad 1/f spectral response, and eliminates interference effects due to finite sample boundaries and adjacent elements. To construct such a uniform, isolated slit that is much longer than the millimeter-scale spot of a THz beam, we use atomic layer lithography to pattern vertical nanogaps in a metal film over an entire 4-inch wafer. We observe an increasing field enhancement as the slit width decreases from 20 nm to 2 nm, in agreement with numerical calculations.